Ecology

The Water Framework Directive is centered on achieving “Good Ecological Status” or “Good Ecological Potential”, with all measures targeting improvements in ecology.

1 WFD Biological Quality Elements

Ecological Overall Status is the overarching classification for ecology, it takes into consideration phys-chem status elements such as dissolved oxygen, phosphorous and ammonia (see Water Quality page) as well as specific pollutants such as Annex VIII substances. We wish to simplify this and provide sight of just biological quality elements on this page so as not to overlap with the evidence shown on the water quality page. Biological quality elements are as follows:

  • Fish

  • Invertebrates

  • Macrophytes & Phytobenthos

The lowest score in a waterbody for the above items is adopted as the “Biological Quality Elements” classification for that waterbody.

In the 2022 interim WFD classification, the Parrett saw 2% of waterbodies achieved Bad, whilst 20% of waterbodies achieved Good, and 4% of waterbodies achieved High.

In comparison, the 2019 WFD classification saw 2% at Bad, with 18% at Good, and 4% at High.

1.1 Reasons for Not Achieving Good

Tip

Use the below ‘Search’ box to to search for a waterbody or classification element and scroll through RNAGs and Measures. Click the ‘Excel’ button to download a spreadsheet.

1.2 Measures

Measures for the waterbodies identified above are shown in the table below.

2 Monitoring Data

The below pop-up plots show the latest interim WFD classification (2022) for the individual elements the make up the WFD Biological Quality Elements. These are visualised at a waterbody and site level.

Invertebrates have been used to assess the ecological health of rivers as they act as biotic indicators for water quality, habitat diversity and hydrological pressures whilst unlike fish or macrophytes, their abundance is less impacted by barriers.

2.1 2022 WFD Fish WB & Site Classifications

Fish can be used to indicate the ecological status of a river. Metrics on river fish composition, abundance and prevalence are run through the FCS2 classification tool. The actual (observed) values for these metrics are compared with a predicted value (reflecting a river in pristine condition). The comparison of the observed to expected values is known as an Ecological Quality Ratio (EQR). EQRs are used to produce a fish classification.

2.2 2022 WFD Macrophytes & Phytobenthos WB & Site Classifications

A combined classification element, macrophytes & phytobenthos have been designed to reflect the impact of nutrient enrichment (predominantly impacting Phytobenthos). It can also be sensitive to some other anthropogenic pressures, including alterations to river flows and modifications to morphological conditions which may act alone or in combination to affect macrophytes.

3 Third Party Data

This initial evidence pack doesn’t include any ecological Water Company data, only data taken directly from the Riverfly Partnership. Third-parties often have a different or un-aligned monitoring agenda to the Environment Agency. Eventually through influence, priorities can be aligned, however, initially data may not be exactly where the EA would require it. Here we view a site mean for citizen science riverfly sites from 2022 onwards.